Surge-Protected Peripheral Devices

ABSTRACT

A computing system including: a host system; at least one device, mechanically connected to the host system, each device having an active state and an inactive state, wherein each device is conductively disconnected from the host system when the inactive state is enabled; and a mechanism for the host system to switch each device between the active state and the inactive state Preferably, at least one device is connected to the host system via a connector. Preferably, the device is hard-wired to the host system. Preferably, some wires of at least one device are isolated from the host system via a mechanical contactor. Preferably, some wires of at least one device are isolated from the host system via an optical isolator. Preferably, the system further includes: a switching battery; and a mechanism for charging the battery when at least one device is disconnected from the host system.

RELATED APPLICATIONS

This patent application claims priority under 35 U.S.C. §119(e) to U.S.Provisional Application No. 60/940,421, filed May 28, 2007, which ishereby incorporated by reference in its entirety.

This patent application is related to U.S. patent application Ser. No.______ of the same inventors, which is entitled “METHODS FOR PROTECTINGPERIPHERAL DEVICES FROM SURGES” and filed on the same day as the presentapplication. That patent application, also claiming priority to U.S.Provisional Application No. 60/940,421, is incorporated in its entiretyas if fully set forth herein.

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to systems for protecting a peripheraldevice in a computing system from damage due to surge currents.

In addition to other capabilities, personal computers provide users withstorage memory for digital content. The amount of media created by auser is increasing due to the pervasive use of portable devices (e.g.digital cameras). Since the media is typically copied to the computerand then erased from the portable device, the personal computer becomesa single storage device for content that has no backup in any otherlocation.

Backup of stored content on personal computers can be a critical concernto business and personal users. Stationary backup devices (e.g. externalhard-disk drives and remote backup services) are not available when theuser is traveling or working off-line. The use of a different locationon a hard-disk drive, or a second hard-disk drive on the same computerfor backup is not always possible. Furthermore, the hard disk itself hassome probability of crashing, either due to extended use or due toextended power cycling. There is a need for built-in, reliable,automatic backup systems that provide the user with confidence thatimportant information on the user's hard disk has a backup.

Additional peripheral devices, connected to a computer, that are notfrequently used (e.g. a business-card scanner, a desktop scanner, aphotograph printer) are also continuously exposed to the risk of surgecurrents, and could benefit from a solution that protects the devicesfrom surge damage without physically detaching the devices from thecomputer.

It would be desirable to have systems for protecting a peripheral devicein a computing system from damage due to surge currents.

SUMMARY OF THE INVENTION

It is the purpose of the present invention to provide systems forprotecting a peripheral device in a computing system from damage due tosurge currents.

For the purpose of clarity, several terms which follow are specificallydefined for use herein. The term “dormant-peripheral network protocol”is used herein to refer to a peripheral device in a computing systemthat is not conductively connected to a host system, and can beconnected and activated by a remote command. The term “surge protection”is used herein to refer to protection of an electronic device from surgecurrents (e.g. currents caused by lightning). The term “dormant backup”is used herein to refer to a built-in backup device that is configuredto have high reliability due to a low usage duty-cycle. The expression“conductively disconnected” is used herein to mean that none of theconducting elements of a device are connected to any of the conductiveelements of a host system.

In a preferred embodiment of the present invention, the use of areliable non-volatile storage device (e.g. a hard-disk drive or aflash-disk drive), which is connected to a host system, increases the“mean time between failures” (MTBF) of the device by several orders ofmagnitude by maintaining the device in a dormant mode (i.e. powered offand electrically-disconnected state from the host system for a majorityof the time, powering the device on only when needed by the host system.

A program running on the host system schedules a backup operation as newcontent is created in the main storage device of the host system. Thebackup operation includes backup of new media files, documents updates,and new e-mail. Periodically, the program instructs a secondarynon-volatile storage device (different than the main storage device)that is operationally connected to the host system, but electricallydisconnected from the host system, to be powered on. Once powered andconnected to the host system, the program backs up the scheduled filesto the secondary device, with or without compression, using methodsknown in the art of software engineering.

Once the content has been backed up and verified, the program powers offthe secondary storage device, and electrically disconnects the devicefrom any galvanic contact with the circuitry of the host system. Theresult is that the secondary storage device is powered on much lessfrequently than the main storage device, and for much shorter periods oftime. These two features of operation extend the life expectancy and theMTBF of the secondary device far beyond those of an alternative devicethat is powered on each time the host system is powered on, and isoperating throughout the session of the host system.

An important aspect of the present invention is that by beingelectrically disconnected from the host system, the secondary device ismuch less susceptible to surge currents caused by power-linefluctuations and by lightning.

In another preferred embodiment of the present invention, the method isapplied to peripherals device other than disk drives (e.g. USB scannersand special printers) that are connected to the host system, and arepowered from the host system. According to the present invention, suchperipheral devices are connected to a USB socket, which is completelydisconnected from any conductive connection with the host system, andare powered and used only when needed.

Therefore, according to the present invention, there is provided for thefirst time a computing system including: (a) a host system; (b) at leastone device, mechanically connected to the host system, each devicehaving an active state and an inactive state, wherein each device isconductively disconnected from the host system when the inactive stateis enabled; and (c) a mechanism for the host system to switch eachdevice between the active state and the inactive state.

Preferably, at least one device is connected to the host system via aconnector.

Preferably, the device is hard-wired to the host system.

Preferably, at least some wires of at least one device are isolated fromthe host system via a mechanical contactor.

Preferably, at least some wires of at least one device are isolated fromthe host system via an optical isolator.

Preferably, the system further includes: (d) a switching battery; and(e) a mechanism for charging the battery when at least one device isdisconnected from the host system.

Most preferably, the system further includes: (f) a mechanism forpowering at least one device using the battery when at least one deviceis connected to the host system.

Preferably, the system further includes: (d) a mechanism for reversiblyconductively connecting at least one device to the host system.

These and further embodiments will be apparent from the detaileddescription and examples that follow.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is herein described, by way of example only, withreference to the accompanying drawings, wherein:

FIG. 1 is a simplified schematic block diagram of a system forconnecting to a protected device using an electromechanical contactor,according to preferred embodiments of the present invention;

FIG. 2 is a simplified schematic block diagram of a system forconnecting to a protected device using an electronic isolated contactor,according to preferred embodiments of the present invention;

FIG. 3 is a simplified schematic block diagram of a commercial opticalswitch/isolator, according to the prior art;

FIG. 4 is a simplified flowchart of the operation of a system forconnecting to a protected device using an electronic isolated contactor,according to preferred embodiments of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to systems for protecting a peripheraldevice in a computing system from damage due to surge currents. Theprinciples and operation for protecting a peripheral device in acomputing system from damage due to surge currents, according to thepresent invention, may be better understood with reference to theaccompanying description and the drawings.

Referring now to the drawings, FIG. 1 is a simplified schematic blockdiagram of a system for connecting to a protected device using anelectromechanical contactor, according to preferred embodiments of thepresent invention. A computing system 20 includes a host system 22 (e.g.a personal computer) that has, among other components, a storage memory24 (e.g. a built-in hard-disk drive) and a host processor 26.

A peripheral protected device 42 (e.g. a backup disk drive) is connectedto computing system 20 via a multi-pin socket 38 (e.g. a standard USBsocket) and a multi-pin connector 40 (e.g. a standard USB plug).Connections A of socket 38 are not electrically connected to host system22. Connections A are connected to isolated ports of a switching unit 32via an electromechanical contactor 34. Electromechanical contactor 34 isconnected to a controller 36 which is controlled by host processor 26via connections B. The other side of contactor 34 is connected to hostsystem 22 using a standard bus connection C.

Host system 22 controls controller 36, via host processor 26, forswitching contactor 34 on and off. In the steady-state situation,controller 36 keeps contactor 34 disconnected. The data lines, VCC line,and ground line (not explicitly shown) are disconnected from protecteddevice 42. Any surge current that may hit host system 22, via a powerline, network cables, or other means connected to host system 22, willnot affect protected device 42.

When there is a need to use protected device 42 (e.g. to perform abackup operation), host processor 26 temporarily instructs controller 36to connect protected device 42 to host system 22. Protected device 42 ispowered, and when ready, host system 22 uses protected device 42 forbackup or for any other function. When the operation is over, hostprocessor 26 instructs controller 36 to disconnect protected device 42and computing system 20 returns to a steady state. Protected device 42can be, for example, a hard-disk drive, or a solid-state drive, or anyother peripheral.

FIG. 2 is a simplified schematic block diagram of a system forconnecting to a protected device using an electronic isolated contactor,according to preferred embodiments of the present invention. FIG. 2shows an electronic embodiment of the present invention that is suitablefor fast digital traffic and for a standard USB connector. A host system50 is connected via a USB link to a controller 52 of a sub-system 54(e.g. a protected USB port). The USB link includes four wires: a VCCline D, a ground line E, and D+/D− data lines F and G, as described inthe USB Specification, rev. 2.0, Chapter 4.2.1—Electrical.

Controller 52 routes VCC line D and ground line E to two ports H and Iof a contactor 56, and routes data lines F and G, via lines J and K, tooptical switches 58 and 60, such as described in the Chapter 2 of Thedigital I/O Handbook (available from SeaLevel Systems, Liberty, S.C.).FIG. 3 is a simplified schematic block diagram of a commercial opticalswitch/isolator taken from The Digital I/O Handbook.

It should be noted that since the D+ and D− signals in the USB protocolare alternately flowing in both directions, each of lines J and Krequires two optical switches for the two opposite directions, but forthe simplicity of the drawing only one is shown for each in FIG. 2 (i.e.switches 58 and 60, respectively). Light-emitting diodes 62 and 64 arein the direction of current flowing towards ground points 66. M isolatedVCC line L is connected to the emitters of optical switches 58 and 60 inthe reverse directions (via lines P and Q), and data lines N and O areconnected to the collectors of optical switches 58 and 60.

Four additional optical switches, driven by data lines N and O foroutputting signal to data lines J and K, are not shown in FIG. 2. Thus,in FIG. 2, optical switches 58 and 60 represent 8 optical switches (i.e.4 switches for input, two for D+ and two for D− signals, and 4 switchesfor output, two for D+ and two for D− signals). For each D+ and D−signal, there are two switches: one switch for the positive current andone switch for the negative current.

A battery 68 is connected between central leads 70 and 72 of contactor56. In the steady-state situation, contactor 56 is controlled, via acontrol line R, by controller 52 to connect lead 70 to a lead 74 andlead 72 to a lead 76. This keeps battery 68 continuously charged.

Sub-system 54 is connected to a peripheral protected device 78 that isdoes not make contact with any conductive contacts of the chassis or thecircuitry of sub-system 54. When lead 80 of contactor 56 is notconnected, isolated VCC line L of sub-system 54 is electricallyisolated, and the collectors of optical switches 58 and 60 (as well asthe switches not shown) are not electrically connected to the circuitryof host system 50. When lead 82 of contactor 56 is not connected, groundline M of sub-system 54 is electrically isolated. Data lines N and O ofsub-system 54 are always electrically isolated because data lines N andO are hard-wired to the emitters of optical switches 58 and 60, and theemitters are not connected to the circuitry of host system 50, andreceive VCC and ground connections through contactor 56.

FIG. 4 is a simplified flowchart of the operation of a system forconnecting to a protected device using an electronic isolated contactor,according to preferred embodiments of the present invention. Thereference numerals of FIG. 2 are used to provide better clarity. Whenhost system 50 needs to use protected device 78 that is plugged insub-system 54 (Step 84), host system 50 instructs controller 52 toactivate contactor 56, via control line R, in order to switch contactor56 to the active position (Step 86). Positive lead 70 of battery 68 isthen connected to isolated VCC lead 80, and negative lead 72 of battery68 is connected to isolated ground lead 82 (Step 88). Optical switches58 and 60 (as well as the switches not shown) are powered and startoperating (Step 90), delivering data signals between host system 50 andprotected device 78 (Step 92).

While the invention has been described with respect to a limited numberof embodiments, it will be appreciated that many variations,modifications, and other applications of the invention may be made.

1. A computing system comprising: (a) a host system; (b) at least onedevice, mechanically connected to said host system, each said devicehaving an active state and an inactive state, wherein said each deviceis conductively disconnected from said host system when said inactivestate is enabled; and (c) a mechanism for said host system to switchsaid each device between said active state and said inactive state. 2.The system of claim 1, wherein said at least one device is connected tosaid host system via a connector.
 3. The system of claim 1, wherein saiddevice is hard-wired to said host system.
 4. The system of claim 1,wherein at least some wires of said at least one device are isolatedfrom said host system via a mechanical contactor.
 5. The system of claim1, wherein at least some wires of said at least one device are isolatedfrom said host system via an optical isolator.
 6. The system of claim 1,the system further comprising: (d) a switching battery; and (e) amechanism for charging said battery when said at least one device isdisconnected from said host system.
 7. The system of claim 6, the systemfurther comprising: (f) a mechanism for powering said at least onedevice using said battery when said at least one device is connected tosaid host system.
 8. The system of claim 1, the system furthercomprising: (d) a mechanism for reversibly conductively connecting saidat least one device to said host system.